Stakeholders use a wide variety of PDF creation programs. eMod should be able to ingest a PDF created using a variety of programs. (e.g., don't require use of PDF creation by use of Vendor X's software) Either use a PDF specification that is open-source, or publish an SDK that could drive development by multiple vendors.
When PDF files are created from scans, for example declarations, they can be at varying resolutions, and be interpreted by EFS as having a page size which is too large. So long as the resolution is sufficient, EFS should be able to automatically resize the file to 8.5x11. Requiring the user to find out how to correct the problem is unnecessary.